1. Field of the Invention
The present invention relates to a gas combustion type driving tool.
2. Related Art
As gas combustion type driving tools, there is known a type of a driving tool in which a fuel container such as a gas can filled with liquefied fuel gas is mounted in the tool, and the fuel supplied from the fuel container is measured by an electromagnetic valve device and then injected into a combustion portion.
In such gas combustion type driving tool, in many cases, the electromagnetic valve device is disposed near the combustion portion and the fuel container is disposed near a grip.
However, when the electromagnetic valve device is disposed nearer to the combustion portion than the fuel container, since the electromagnetic valve device is easier to be influenced by a heat of the combustion portion, a temperature of the electromagnetic valve device becomes higher than that of the fuel container.
In the case that the electromagnetic valve device becomes higher in temperature than the fuel container, when a liquefied gas is supplied from the fuel container to the electromagnetic valve device, the liquefied gas is vaporized within a gas pipe line due to the temperature difference between the fuel container and electromagnetic valve device, resulting in a poor fuel combustion to thereby prevent the driving tool against proper operation.
To avoid such problem, the temperature of the fuel container must be set substantially equal to or higher than that of the electromagnetic valve device.
For example, in a gas combustion type driving tool disclosed in U.S. Pat. No. 5,263,439, an electromagnetic valve device and a fuel container are disposed at equal distance from a combustion portion. When amounts of heat transmission from the combustion portion to the fuel container and electromagnetic valve device are equal, their respective influences can be made almost equal, thereby being able to control the temperature difference between the fuel container and electromagnetic valve device.
However, in the gas combustion type driving tool disclosed in U.S. Pat. No. 5,263,439, since the fuel container is interposed between the combustion portion and a grip portion, a grip must be disposed shifted backward by an amount equivalent to a size of the fuel container. Therefore, a position of a trigger must also be shifted backward, which worsens a balance of the whole driving tool.